The objectives of the proposed research are to understand the characteristics and origins of electrical potentials recently discovered in the human visual system, and to investigate their behavior in various diseases and anomalies affecting vision: 1. Early oscillatory electrical potentials have been recently recorded from the occipital area of the scalp in the visual evoked cortical potential (VECP), which bear a resemblance to the oscillatory potentials of the electroretinogram (ERG), although displaced in time. It is proposed to investigate the temporal relationships of these oscillatory potentials (VECP to ERG), the relationship of early VECP oscillatory activity to later VECP slow wave activity, the spectral sensitivity, and the behavior of VECP oscillatory activity in selected clinical patients. 2. Electrical potentials have been recently recorded from the region of the "temple" (caudal to the fronto-zygomatic suture, on a level with the eye). It is proposed to determine whether all or some part of these potentials arise from the anterior segment of the optic nerve, and to differentiate these potentials from the "far-field" volume conduction recording of ERG and VECP. In addition, it is proposed to investigate the behavior of these potentials in selected neurological patients.